Data transfer networks include network elements such as, for example, routers, switches, and terminal devices which communicate with each other via data transfer links between the network elements. In many data transfer networks, there is a need to distribute clock-time information among the network elements. The network elements can be arranged to constitute master-slave pairs so that each master-slave pair operates as a phase synchronized loop and the clock time information prevailing at the master-end of the phase synchronized loop is transferred to the slave-end of the phase synchronized loop. Timing protocols, e.g. a timing protocol according to the IEEE 1588 specification (Institute of Electrical and Electronics Engineers) can be implemented to transfer the clock-time information from the master-end to the slave-end.
Typically the timing protocols are implemented in a way that the actions related to a timing protocol under consideration are carried out in several interconnected units of a network element. For example, time stamping and other time critical actions are usually carried out in transceiver units of the network element whereas some other actions, such as computations, are usually carried out in the CPU (Central Processing Unit) of the network element. This means that the different interconnected units of the network element have to be compatible with each other so that these units form together a system capable of running the timing protocol being used. This requirement increases the complexity and many times also the price of the network element.